Process of manufacturing bimetallic appendixes for monometallic balances



Dec. 4, 1934. p D|T|$HE|M 1,982,726

PROCESS OF MANUFACTURING BIMETALLIC APPENDIXES FOR MONOMETALLIC BALANCES Filed March 26, 1932 7 w; 65% @ZZZMZM'W Patented Dec. 4, 1934 PROCESS OF MANUFACTURING BIMETALLIC APPENDIXES FOR MON OMETALLIC BAL- ANCES Paul Ditisheim, Paris, France Application March 26, 1932, Serial No. 601,426 In Switzerland April 2, 1931 Claims.

The present invention relates to a process of manufacturing bimetallic appendixes for monometallic balances combined with a spiral made of an alloy called Elinvar.

The complicated composition of the Elinvar, the difference of the densities and of the melting points of its components and also the difference of its homogeneity resulting partly from the wiredrawing process, from the rolling and from the shaping of the spirals are as many items which influence the compensating qualities of a spiral made of said alloy. In order to amend the defects of the different casting processes and the discrepancies between one spiral and another turned out by the same casting process it has been proposed to combine with spirals of Elinvar monometallic balances having a suitable linear dilatation and to which according to the established discrepancies compensating bimetallic bodies have been fixed either on the inside or the outside of the rim.

The compensating fixtures used heretofore have been manufactured according to the process employed for the split bimetallic compensating balances. In a perforated steel disk a very deep furrow was out which was filled with brass. Then the bimetallic cylinder thus obtained was turned on its inside and on its outside to obtain the desired thicknesses of metal. From such a ring generally six fixtures were cut out, or rather three pairs of a given curvature as obtained by the turning process.

It is certain that such fixtures were rather expensive and therefore the manufacture of this 35 kind of compensating fixtures was hindered very much.

The object of the present invention is a manufacturing process of bimetallic fixtures or appendixes for monometallic balances combined with spirals made of Elinvar which leads easier and at a less expense to the desired result.

The starting body for this new process is a bimetallic body having a very extended plane surface. The fixtures are cut out from such a body either by a press, a saw, or any other means and are bent to the desired curvature. The bimetallic band may be rolled helicoidally around a cylinder having the desired curvature and by a repeated reheating the molecular stabilization is assured. Then the helicoidal band is cut up into the several fixtures and before finishing these latter the holes for the fixing screws have been drilled and the holes for the compensating screws generally used with such members.

The annexed drawing shows,

as far as it is rethe new process.

The Figures 1 and 2 show the way heretofore followed for manufacturing bimetallic appendixes.

The Figures 3 and 4 show the new way for obtaining the same appendixes,

and

The Fig. 5 represents a bimetallic band, the cross section of which is shown in Fig. 6 while the Fig. '7 shows a drum around which said bimetallic band has been wound for pendixes the desired curvature.

giving to the ap- With reference to the Figures 1 and 2 of the annexed drawing a is a steel disk having a very deep furrow b which is filled with borax and on which a brass ring 0 has been deposited. The whole is put into the fire until the brass has melted and has filled the furrow completely. The bimetallic cylinder thus obtained has to be turned in order to obtain a bimetallic ring d (Fig. 2) into the periphery of which the required holes for the fixing screws are drilled and the holes for holding the compensating screws. By means of such a bimetallic ring six appendixes may be obtained having a given curvature. This is the old manufacturing process.

In the process according to the present invention a bimetallic band e is p repared, such as shown in the Figs. 5 and 6, by plating the two metals one upon the other or by galvanizing one metal upon the other: such a band may also be obtained by casting one metal upon the other or by uniting the two metals by a wire-drawing or a rolling process.

A bimetallic band is called here a band composed of two metals having different coefficients of dilatation band is held fixed to one side or the so that when the at one end the band will bend other according to the changes of temperature of the circumambient medium to which it has been submitted As said band is perfectly pl ane and has the desired dimensions the holes for the fixing screws and for the compensating screws may be drilled at the desired distances be wound around a drum as sh Then the whole may own in Fig. 4 the curvature of which corresponds with that of the rim of the balance which is to the manufactured appendixes. band will be fixed to the drum ing, and after the winding the be provided with One end of the before the windother end of the band will be fixed likewise. After this the molecular stabilization will be ass ured by any of the reheating processes known in metallurgy.

By the process it is possible to wind at wish the most dilatable metal around the inside or the outside according to the efiect of the thermic variations in advance or in slowness which have to be taken into account.

After having withdrawn the helicoidal band metallic balances so as to correct the defects connected with a given Elinvar spiral. That is to say, as in the case of the Fig. 3,. thatthe screws ,f shall become approached to the rim g when the temperature is rising or that said screws, as in the case of the Fig. i, shall be re- .moved from the -rim 9' likewise when the temperature is rising.

By choosing dilative metals of more or less divergences it is-possible to obtain at wish more or less important corrections for the advance or forthe slowness. It is also possible to arrange .the'ap-pendixes so that nonmagnetic metals are used or metals which do not keep up some remnant magnetism.

What I claim is:

1. A method of making compensating balances that include a monometallic wheellused with a hairspring of Elinvar which includes the acts of first forming a bimetallic body:in anextended flat form of an areafrom which a number ..of:such'attachments may be cut thereafter cutting pieces from such body of the required dimensions. for an attachment, curving the pieces-in I correspondence with the curvature of the balance ,rim to which they are to beattached, and attach- ..ing the same to the monometallic wheel.

2. A method of making bimetallic compensatuing attachments for monometallic balances used witha hairspring of Elinvar which includes-the acts of first forming a bimetallic body in an extended fiat form of an area from which a number of such attachments may be cut, curving such body in-correspondence with the curvature of :the

balance rim to which it-is to be attached, and

thereafter cuttingpieces from such body of the required dimensions for -an attachment.

3. A method of making compensating balances .--that-include amonometallic wheelused'with a hairspring of Elinvar which includes the acts of firstforming a bimetallic body in an extended fiat .form of an area -fromwhich a number of such --a.-ttachments maybe out, performing upon such body the operations-required to fit it for its use an attachment, and thereafter cutting pieces .fro-msuch body of the required dimensions for an attachment and attaching'the same to the mono- .metallic wheel.

4. A method of making bimetallic compensating attachments for monometallic balances used with a hairspring of Elinvar which includes the acts of first forming a bimetallic body in an extended fiat form of an area from which a number of such attachments may be cut, giving such body a helical form of a curvature corresponding with :the curvature of the balance with which the attachment is to be used, and thereafter cutting -pieces from such body of the required dimensions for an attachment.

5. A method of making compensating balances 'xthat include 'amonometallic wheel used with a hairspring of Elinvar which includes the acts of forming a straight band of united layers of metal, the surfaces of the band being plane and thereafter cutting such band into a number of pieces '.each-:of-.a suitablelength for attachment to a nbalancewheel, curving the pieces in correspondencewith the curvature of the balance rim to which they are to be attached, and attaching the same to the monometallic wheel.

- 6. A-method of making bimetallic compensating attachments for monometallic balances used with a hairspring of Elinvar which includes the acts of forming astraig'ht band of unitedlayers of metal, the surfaces offthe band being plane, giving: to such body a curvature in correspondence with the curvature ofthe balance with whichthe attachment is to'be used, andthereafter cutting such bandinto a number of pieces each of a suitable length for attachment to a balance wheel.

' 7. A-.methodv of making balance wheels used with a hairspring of Elinvar which includes'the stepsv ofmakinga bimetallic body of metals that have a-compensating relation, 'of plane form ofextended length, curving'suchbody into correspondencewith .the curvature of the rimof a monometallic balance, cutting such body into lengths suitable for attachment to a monometallic balance, andthen attaching such a length atone,

end to amoncmetallic balance.

8. A method as in claim 2 in whichafterthe step of curvingthe body, the same is s'ubjectedto heat'treatmentto produce molecular stabilization. .9.'A'method .as in; claim Tin which afterthe step of curving the bodyythe same is -subjected to heat treatment to; produce molecular stabilization.

1c. Amethodjof making balances that includes the acts of providing amono-metallic wheel for,- use with a hairspring requiringtemperature compensating attachments, forming a bi-meta-llic body in an extended fiat form of an-area from which a number of such attachments may be cut,

thereafter cutting pieces from such 7 body oi an gular extent substantially. less than the: circum ference of the mono-metallic wheel, curvingsuch piece in correspondence-with the curvatureiiof the balance rim-before such pieceis cut therefrom,

and then attachingsuch-pieceto thebalancecir cumference with asubstantial'portion of the piece free from' the wheel.

DITISHEIM. 

